BALTIMORE -- Red Sox reliever Carson Smith will undergo shoulder surgery on Wednesday in New York and is almost certain to miss the rest of the season, manager Alex Cora announced.

Smith, who made 18 appearances with the club this season, injured his shoulder throwing his glove in frustration after a poor outing against the Athletics on May 14. He has since had three opinions on the injury, with the consensus being that surgery was the necessary option.

"Carson had subluxation of his right shoulder," said head athletic trainer Brad Pearson. "Anytime you have a subluxation, you'll want to evaluate the structures in the shoulder. We found some suspicion in the labrum and the capsules."

"They're gonna go in and look at all the structures and fix everything they feel is necessary to add stability back to that shoulder so he can handle the rigors of pitching and throwing," Pearson said.

Pearson said there is no definite timetable for Smith's return and that more will become clear after the surgery.

Smith, who was acquired in a trade with Seattle during the 2015 winter meetings, has made only 29 appearances for the Red Sox in parts of three seasons. He underwent Tommy John surgery in May 2016 and missed most of the 2017 and 2018 campaigns before returning healthy at the beginning of this year.

"There's a first for everything," Pearson said. "It's not something I would've typically seen, but he threw it pretty hard, and it's possible we found out that's another way you can hurt your shoulder."